@divino5118
You haven't provided enough detail of your situation.
See the reply right above your question. It covers most situations. But, it is not for 2021.
For 2021, there's something new: the enhanced and fully refundable child tax credit. You may get a $500 credit for claiming the child, but your girlfriend loses out on $3000 (maybe $3600), even if she has no income.
